Electrostatic methods may be utilized in many applications, such as combustion of fuels and manufacture of fibrous materials.
Certain methods of electrostatic atomization of liquids are known. These methods use an electrode defining an orifice. The liquid is passed through the orifice, from a first side of the electrode to a second side. An oppositely charged surface is remotely disposed with respect to the electrode, on the second side of the electrode. These methods require large potential differences developed over the large air gap between the orifice and the charged remote surface. The electric field developed over the air gap is relied upon to develop the necessary charge within the fluid and disperse the fluid into droplets.
In certain embodiments, U.S. Pat. No. 4,255,777 discloses a system for atomizing fluids. As taught in certain embodiments of U.S. Pat. No. 4,255,777, the disclosure of which is hereby incorporated by reference herein, a fluid may be passed between a pair of opposed electrodes before discharge through the orifice. These opposed electrodes are maintained under differing electrical potentials, so that charges leave one of the electrodes and travel towards the opposite electrode through the fluid. However, the moving fluid tends to carry the charges downstream, towards the discharge orifice. Generally, the velocity of the fluid is great enough that most of the charges pass downstream through the orifice and do not reach the opposite electrode. Thus, a net charge is injected into the fluid by the action of the opposed electrodes. Systems according to certain embodiments of U.S. Pat. No. 4,255,777 can apply substantial net charge to the fluid and hence can provide superior atomization, as compared to the above-discussed known method.
The throughput for such devices can be important for commercial applications utilizing electrostatic methods, such as atomization of liquids, formation of fibers, or application of coatings. In addition, the efficiency and the even dispersal of the fluent material across a given area can be important. Despite considerable effort to develop electrostatic methods, further work is desirable.